/*
 * Copyright 2024 LiveKit
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import Foundation

//
// Read http://www.russbishop.net/the-law for more information on why this is necessary
//
class UnfairLock {
    private var _lock: UnsafeMutablePointer<os_unfair_lock>

    init() {
        _lock = UnsafeMutablePointer<os_unfair_lock>.allocate(capacity: 1)
        _lock.initialize(to: os_unfair_lock())
    }

    deinit {
        _lock.deinitialize(count: 1)
        _lock.deallocate()
    }

    func sync<Result>(_ fnc: () throws -> Result) rethrows -> Result {
        os_unfair_lock_lock(_lock)
        defer { os_unfair_lock_unlock(_lock) }
        return try fnc()
    }
}
